JPH0536376U - Current detector - Google Patents

Abstract

(57) [Abstract] [Purpose] A magnetic sensitive element is arranged in the air gap of a magnetic core provided with a magnetic air gap in a magnetic path, and a conductor to be detected is wound around the magnetic core to detect the value of the current to be detected. In the current detector configured to detect the output voltage of 1), the storage case that houses the magnetic core and the magnetic sensitive element is peeled off to provide an inexpensive current detector that is easy to assemble and has a small board mounting area. [Structure] A magnetic sensitive element 2 and a circuit component 4 for amplifying the output of the magnetic sensitive element as a voltage output and a trimming resistor are mounted on the front surface of the circuit board 1, and the back surface of the magnetic sensitive element mounting surface of the circuit board 1 is covered. A U-shaped conductor for passing a detection current is attached, signal input / output terminals 7 are attached inside the detection current input / output terminals 6a and 6b at both ends of the U-shaped conductor, and the magnetic core 2, the circuit board 1 and the circuit component 4 are resin-molded. To form.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a current detector used in a device for detecting a current and controlling a current in an electronic device.

[0002]

[Prior Art]

 As shown in FIG. 4, a conventional current detector of this type stores a magnetic core 13 having a magnetic gap in a magnetic path in a core case 15 and sends a current to be detected to a coil 14 wound around the core case. The magnetic sensitive element 11 is arranged in the magnetic gap, the circuit board on which the magnetic sensitive element and the circuit parts are mounted is housed in an outer case made of an insulating resin, and the detection current flowing through the coil is arranged in the magnetic gap. The current detector is configured to detect by.

[0003]

[Problems to be solved by the device]

 Such a conventional current detector has the following problems. B) In order to wind the coil around the coil case, it is necessary to rely on human labor, which requires an outer case and a core case, which is expensive. In addition, for the outer case and core case, the initial investment cost is high because a mold is required when forming the case. B) It is difficult to downsize because it uses an outer case or core case. Therefore, the occupied area becomes large when mounted on the board. C) Since it is the solder joints of the coil lead terminals and input / output terminals that hold the current detectors on the mounting board, reinforcing pins are required for further reinforcement in order to obtain strong vibration resistance. Get expensive. D) During cleaning, the cleaning liquid enters the inside of the case through the gap between the case and the input / output terminal insertion hole of the case, and remains inside the case as it is, causing corrosion of components and conductors, which leads to poor reliability. Had a point.

[0004]

[Means for Solving the Problems]

 In order to solve the above problems, the current detector according to the present invention has the following configuration. B) A U-shaped busbar made of a metal plate with good electrical conductivity is arranged so that it penetrates the inside diameter of the magnetic core, and the end of the busbar is used as an input / output terminal connected to an external conductor through which a current flows. Form a single turn winding that couples to the magnetic core. (B) The current input / output terminals of the bus bar terminals and the signal input / output terminals of the circuit board are arranged on the same end face of the circuit board to form the board mounting terminals. Since the cross-sectional area of the metal plate forming the busbar can be selected arbitrarily, the structure of the current input / output terminal of the busbar terminal with a large cross-sectional area and the portion where the signal input / output terminals are soldered to the mounting board can be changed arbitrarily. Since it can be used, it is structurally sufficiently compatible with applications that require strong vibration environments. C) Since the circuit board, magnetic core, magnetic sensitive element, etc. are integrally molded with a resin mold, it is easy to wash and dry, and the core case and outer case are unnecessary, and the unit price of the product can be reduced. There is no need for initial investment such as molds. Also, the conductor through which the detection current flows is a U-shaped busbar conductor, and the circuit parts are mounted on the front surface of the circuit board and the busbar is mounted on the back surface. Reduce the mounting area.

That is, the present invention is as follows. A magnetic sensing element is placed in the magnetic gap of a magnetic core with a magnetic gap in the magnetic path, a conductor that conducts the detected current is wound around the magnetic core, and the value of the detected current is used as the output voltage of the magnetic sensing element. In a current detection circuit configured to detect, a magnetic sensitive element is inserted into the magnetic air gap provided in the magnetic core, and it is composed of a magnetic sensitive element on one side and an amplifier circuit and a drive circuit for amplifying the output of the magnetic sensitive element. Provide the circuit board on which the circuit parts are mounted and the conductor of the U-shaped bus bar that penetrates the inner diameter of the magnetic core is arranged on the back side, and connect the current input / output terminals of both terminals of the bus bar to the signal input / output of the circuit part. The current detector is characterized in that the magnetic core, the magnetic sensitive element, and the circuit component are mounted on both sides of the terminal by resin molding. 2. 2. The current detector according to claim 1, wherein a resin film sheet having an electrically insulating property is interposed between the magnetic core and the magnetic sensing element or between the magnetic core and the bus bar.

[0006]

[Action]

 On one surface of the circuit board, a magnetic sensing element, a circuit component consisting of an amplifier circuit that drives the magnetic sensing element and amplifies the output voltage of the magnetic sensing element, and a trimming resistor, and the surface of the circuit board where the magnetic sensing element is mounted. Attach a U-shaped bus bar that carries the detected current on the back side, and attach current input / output terminals at both ends of the bus bar on both sides of the circuit board and signal input / output terminals inside both ends of the bus bar. It is a current detector in which a magnetic sensor with a magnetic element provided in the gap and a gap corresponding to the thickness of the circuit board is assembled, and the magnetic core, circuit board, and bus bar are integrally covered and fixed with resin. The current detector is easy and has a small board mounting area.

[0007]

【Example】

 An embodiment of the current detector of the present invention will be described with reference to the drawings. 1 to 3 show an embodiment according to the present invention, FIG. 1 is a front configuration diagram, FIG. 2 is a sectional configuration diagram, and FIG. 3 is a partially cutaway perspective view of a rear face showing a bus bar side. The magnetic sensitive element 3 that is inserted into the magnetic air gap of the magnetic core and detects the magnetic field created by the detection current flowing in the bus bar in the magnetic air gap, the circuit component 4 that amplifies the output of the magnetic sensitive element, and the gain and drift of the output amplifier circuit are A circuit board 1 on which a signal processing circuit having a trimming resistor 5 to be adjusted is formed, and a bus bar 6 of a metal plate made of a good U-shaped conductor on the surface opposite to the surface on which components are mounted is adhered to a circuit board. Fix with. At this time, both terminals of the signal input / output terminal 7 for driving the magnetic sensitive element and amplifying the output of the magnetic sensitive element and the bus bar 6 which is the detection current input / output terminals 6a and 6b are arranged side by side on both end surfaces of the circuit board. To do. As shown in FIG. 2, the magnetic sensitive element 3 on the circuit board 1 is disposed between the magnetic air gaps 9 of the magnetic core 2 in the magnetic core 2 of the toroidal type having the magnetic air gap 9 and having a high relative magnetic permeability characteristic. The bus bar 6 located at, and through which the detection current flows is disposed so as to penetrate through the inner diameter of the ferromagnetic core 2, and the bus bar 6 is fixed to the circuit board 1 by adhesion or the like. The magnetic core 2 and the bus bar 6 fixed to the circuit board 1 by adhesion or the like are further resin-molded by a powder coating method or a resin dipping method, so that the circuit board, the magnetic core, the magnetic sensitive element, the circuit. The parts have a strong integrated structure. When a current to be detected is applied between the detection current input / output terminals 6a and 6b of both terminals of the bus bar 6, a 1-turn winding is formed in the magnetic core and a magnetic field corresponding to the value of the current flowing in the bus bar is generated. It occurs between the magnetic gaps 9 of the core 2. The magnetic field in the magnetic gap 9 is converted into a voltage signal by the magnetic sensing element 3 such as a Hall element that outputs a voltage proportional to the magnetic field generated in the magnetic gap arranged in the magnetic gap 9. The voltage is amplified by the amplifier circuit formed in the circuit component 4 in the subsequent stage of the element 3, and the output signal is output to the external conductor via the signal input / output terminal 7. That is, with the structure of the current detector according to the present invention, it is possible to generate a DC voltage output signal at the output of the magnetic sensing element according to the value of the detected current flowing through the bus bar 6. Further, since the amplification degree and the offset voltage are adjusted in the amplifier circuit, the trimming resistor can adjust the output signal with high precision by laser trimming on the circuit board. In addition, by inserting and arranging an electric insulation sheet between the magnetic core 2 and the bus bar 6 or between the magnetic core 2 and the magnetic sensitive element 3, the electric power between the magnetic core and the bus bar, or between the magnetic core and the magnetic sensitive element can be improved. Guarantee dielectric strength.

[0008]

[Effect of the device]

 Since the present invention is configured as described above, it has the following effects. B) The structure is simple and the winding and case are not required, so the cost can be reduced. B) Since the cross-sectional area of the bus bar can be selected arbitrarily, the cross-sectional area of the current input / output terminals can be increased and the vibration resistance characteristics during mounting are strong. C) Since it is covered with a resin mold, it can be easily washed and dried. D) Since it can be made thin, the board mounting area can be reduced.

[Brief description of drawings]

FIG. 1 is a front view showing an embodiment of a current detector according to the present invention.

FIG. 2 is a sectional view of a current detector according to the present invention.

FIG. 3 is a partially cutaway perspective view of a back surface of a current detector according to the present invention.

FIG. 4 is a side view of a conventional current detector.

[Explanation of symbols]

 1 Circuit Board 2, 13 Magnetic Core 3, 11 Magnetic Sensing Element 4 Circuit Component 5 Trimming Resistor 6 Bus Bar 6a, 6b, 16 Detecting Current Input / Output Terminal 7, 17 Signal Input / Output Terminal 8 Mold Resin 9 Magnetic Air Gap 12 Outer Case 14 Coil 15 Core case 18 Reinforcing pin

Claims (2)

[Scope of utility model registration request] 1. A magnetic sensing element is disposed in the magnetic gap of a magnetic core provided with a magnetic gap in a magnetic path, and a conductor for conducting a detected current is wound around the magnetic core to sense the value of the detected current. In a current detection circuit configured to detect as an output voltage of an element, a magnetic sensitive element is inserted in a magnetic gap provided in a magnetic core, and a magnetic sensitive element on one surface and an amplifier circuit for amplifying the output of the magnetic sensitive element A circuit board having a U-shaped busbar conductor penetrating the inner diameter of the magnetic core is provided on the back side, and the current input / output terminals of both terminals of the busbar are connected to the signal of the circuit part. A current detector characterized in that it is mounted on both sides of an input / output terminal and is formed by molding a magnetic core, a magnetic sensitive element and a circuit component with resin. 2. The current detector according to claim 1, wherein a resin film sheet having an electrically insulating property is interposed between the magnetic core and the magnetic sensing element, or between the magnetic core and the bus bar.